Reinforced concrete construction

ABSTRACT

An improved reinforced concrete construction is provided. The invention is concerned primarily with large, thick reinforced concrete structures of the type used for base slabs for reactors of nuclear power plants, which slabs may be in the order of six to fourteen feet in thickness and measure from one hundred to two hundred feet across. Such structures include mats of reinforcing bars extending thereacross with generally mutually perpendicular junctures, at both lower and upper portions thereof. The upper mat of reinforcing bars is carried on special supporting frames, including uprights and cross bars, which are used to support Ibeam stringers on which the upper reinforcing bars rest. The supporting frames are prefabricated and can be set up rapidly, thereby reducing construction time along with associated labor and other costs. The frames are also specially braced to enable them to be positioned in vertical planes through which the stringers extend.

United States Patent 1191 Aug. 13, 1974 Chancey et a1.

REINFORCED CONCRETE [54] 3,650,081 3/1972 McCracken 52/650 XCONSTRUCTION 3,721,058 3/1973 Dewey, Jr. et a1 52/260 X [76] Inventors.finiesRg ihancefigolliuiy. .lfadies Primary Examiner prank L Abbott gg gi i Assistant Examiner-Carl D. Friedman Richmond Va 53223 Attorney,Agent, or Firm-Allen D. Gutchess, Jr.

[ PP -I 1 7,623 An improved reinforced concrete construction isprovided. The invention is concerned primarily with 52 us. 01 52/292,52/169, 52/648, large, thick reinforced eeherete Shuewree of the type 55 52/678, 52/414 used for base slabs for reactors of nuclear power 511111. C1 E02d 27/08, 1302a 27/32 Plants, Whieh Slabs may be In the Orderof Six to four- [53] Field of Search 52 678, 646, 648, teen feet inthickness and measure from one hundred 52/650, 30, 82 260 600, 319, 3 77to two hundred feet across. Such structures include 684486, 340, 414,282, 284 383 mats of reinforcing bars extending thereacross withgenerally mutually perpendicular junctures, at both [56] ReferencesCited lower and upper portions thereof. The upper mat of UNITED STATESPATENTS reinforcing bars is carried on special supporting frames,including uprights and cross bars, which are 1,115,387 10/1914 Brown52/678 X used to support Lbeam stringers on which the upper 222;: 2 72reinforcing bars rest. The supporting frames are pre- 25s9021 3/1952ONeailll... IIIIIIIIII 52II69 x i be setupfapidly Fhereby reducing3:O06:l 15 10/1961 Hillberg 52/678 cohstmchon along wlth assoclatedlabor and 3,233,374 2/1966 Micheels B131 52/650 x other eests- Theframes are also Specially braced to 3,245,191 4/1966 Ernst 52/686 enablethem to be p ioned in ertical planes 3,427,777 2/1969 Crowley 52/80 Xthrough which the stringers extend. 3,564,803 2/1971 Breeze et al.52/650 X 3,570,206 3/1971 Armistead 52/383 x 7 Clalms, 5 DrewmgFlglll'es ll/ s a? e *7 Z a k;

PAIENTEB NIB 1 31974 SHEEIIUFS mlil 'f FlCif) INVENTOR JAMES C. CHANCEVLEONA/PD C. ELL/5, BY JR...

ATTORNEY PAIENIEU ms 1 31924 SHEET 2 (If 3 INVENTOR JAMES C. CHANCEVLEONA/P0 C, E 5 d BY I :FIGZ- MBM L ATTORNEY PAIENTEBAIJBIIBIQH SHEEI 30F 3 g mv ow mm om ww om mm v INVENTOR JAMES C. CHANCEV EO/VAPD C.ELL/5,//a. wamh ATTORNEY REINFORCED CONCRETE CONSTRUCTION This inventionrelates to an improved concrete construction and particularly to a thickreinforced concrete slab.

Huge, thick reinforced concrete slabs are used for bases of nuclearreactors at nuclear power plants. A typical slab of this nature iscircular'in shape, measures 175 feet in diameter and is feet thick. Suchslabs require heavy reinforcement to maintain stability and preventcracking in the case of earthquakes, etc. Heretofore, thereinforcementfor such a slab has consisted of a mat of reinforcing barsin several criss-crossing layers located near the supporting surface onwhich the slab is poured, along with an upper mat of reinforcing barsspaced from the firstand locatednear the upper surface of the slab. Theupper reinforcing bars have been supported heretofore by a network ofsteel beams cut to length and welded at the job site to maintain them intheir predetermined spaced relationship with respect to the lowerreinforcing bars-prior to the pourin g of the concrete. Thisconstruction has required considerable labor costs. and a substantialamount of construction time which also adds to the overall cost ofconstruction, including increased financing costs, etc.

In accordance'with the'invention, special prefabricated supportingframes, including adjustments for levelling the supported reinforcingmembers, position the,

upper reinforcing bars .and specifically stringers upon which they restat predetermined positions. In a particular form, the stringers extendradially from a central portion of theslab toward the periphery thereof.The frames for supporting the stringers are positioned in verticalplanes extending parallelly tothestringers with adjustable jacks locatedon the frames to engage and support spaced portions of the correspondingstringers. Diagonal braces connect pairs of the frameswith the bracesbeing of 'special'length to enable the braced frames to be positioned ina diverging relationship corresponding to that of the supportedstringers.

It is, therefore,.a principal object of the invention to provide animproved reinforced concrete construction.

Another object of theinvention is to provide a reinforcing structure forconcrete, which structure includes prefabricated, adjustable supportsfor upper reinforcing members of the structure.

Still another object of the invention is to provide an improvedreinforced concrete structure which can be fabricated more rapidly andwith less cost than heretofore.

Other objects and advantages of the invention will be apparent from thefollowing detailed description of a preferred embodiment thereof,reference being made to the accompanying drawings, in which:

FIG. 1 is a somewhat schematic view in perspective of a reinforcedconcrete structure in the process of construction at a plant site;

FIG. 2 is an enlarged, schematic, fragmentary, plan view of thestructureof FIG. 1;

FIG. 3 is a view in elevation taken along the line 3-3 of FIG. 2;

FIG. 4 is a view in perspective of braced supporting frames used tosupport some of the reinforcing members of the reinforced concretestructure; and

FIG. 5 is an enlarged, fragmentary view taken along the line 5-5 of FIG.4.

Referring to FIG. 1, a job site indicated generally at 10 can be thesite of a nuclear power plant, by way of example. It is essential atsuch plants that maximum support be provided for the nuclear reactorcontainment, particularly to minimize shock or vibration and to preventpossible damage to the reactor and subsequent emission leakage in theevent of an earthquake. It is common practice to excavate the site downto a firm foundation, with the diameter of the. excavation exceeding theultimate diameter of the slab to be constructed for the reactor. Asupporting surface 12 is then established either by levelling the groundat the desired depth or bypouring a layer of concrete on the ground toprovide, in either event, a relatively smooth or level, firm supportingsurface. A slab or concrete reinforcement generally indicated at 14 issubsequently fabricated on the surface 12.

Referring particularly to FIG. 3, the concrete reinforcement 14 includesa lower mat or network 16 of lower reinforcing bars supported on or nearthe surface 12 and an upper mat or network 18 of upper reinforcing barssupported above the mat 16 near the upper level of concrete 20 which issubsequently poured over the entire reinforcing structure 14 to providea large r reinforced concrete slab or base 22.

' The lower. mat 16 of reinforcing bars includes a lower layer of bars24 which are supported directly on the surface- 12 or may be supportedoff the surface 12 slightly by chairs. These bars are disposed incircular patterns concentric with the slab 22. Bars 26 of a second layerextend radially and are generally perpendicular to the bars 24 at theirjunctures. Bars 28 of a third layer also extend circularly andconcentrically with the slab, with the radial bars 26 being between thebars 24 and 28. The particular number of layers, disposition,

and size. of the reinforcing bars in the lower mat 16 will depend on thesize and physical characteristics desired for the particular reinforcedstructure 22 being made,-

and are subject to wide variation.

. way of example. These are at different levels in order to accommodatedifferent numbers of layers of the upper reinforcing bars. On the outerstringers 30, all of which extend radially, there are fourlayers ofreinforcing bars including a lower layer of bars 38 extending in acircular pattern, another layer of bars 40 extending radially, anadditional layer of bars 42 extending circularly, and an upper layer ofbars 44 again extending radially. The bars 40 and 44, in this instance,have outer down-turned end portions extending adjacent an outerperipheral wall 46 built of concrete block.

Atan intermediate portion of the slab, the stringers 32 are at aslightly higher level to support only three layers of thereinforcingbars, including a lower circular layer of bars48, a layer of radiallyextending bars 50, and an upper layer of circular bars 52. The stringers34 are at still a higher level and support only two layers ofreinforcing bars, a lower one including circular bars 54, and an upperone consisting of radially extending bars 56. Stringers 36 areintermediate the stringers 30 and are at the same level as the stringers30 to aid in supporting the outer four layers of reinforcing bars. Byvarying the levels of the stringers 30-34, the upper layers ofreinforcing bars in each instance will be at the same level and at agiven distance below the upper surface of the concrete slab 22, eventhough different number of layers of the bars are used at differentportions of the slab.

Central stringers 58 also support two layers of bars 59 and 60, in thisinstance, these bars being disposed in a generally square pattern in-thecentral portion of the slab 22.

It is to be understood that the reinforcing bar construction discussedabove is only illustrative, although fairly typical, of an averagenuclear plant slab base installation. Each site may have its own specialdesign depending on the width and thickness of the slab as well as othergeological and physical characteristics of the specific location. Also,details of the construction such as the location of expansion joints andthe specific construction of the central portion of the slab are notdiscussed.

Referring to FIG. 4, the stringers or reinforcing members 30-36 aresupported in predetermined, spaced relationship to the lower reinforcingmembers 24-28 by a multiplicity of supporting frames indicated at 62.The frames 62 are preferably located in vertical planes in which thestringers 30-34 also are located so that each frame supports itscorresponding stringer at spaced points or locations. Some of the framesmay support one end portion of one stringer and another end portion ofan aligned stringer, as shown in FIG. 3.

Each of the supporting frames 62 includes uprights or legs 64 and 66connected by cross bars 68 and 70. The lower portions of the legs 64 and66 are strengthened or stiffened against bending movement by curved bars72 and struts 74. Also, vertical struts 76 are affixed between the crossbars 68 and 70. Each of the frames 62 is prefabricated with the aid of ajig with the various elements of the frame precut and welded in the jigprior to being brought to the job site.

Each of the legs 64 and 66 is supported on a pedestal 78 having acentral stud or projection (not shown) fitting into the lower end of thetubular leg. At the upper end of each of the legs 64 and 66 is anadjustable jack 80 (see also FIG. 5) comprising a threaded shaft 82 of adiameter to fit inside the upper end of the corresponding leg 64 or 66.A leveling nut and handle 84 has a central portion threaded on theshaft82 and, in turn, is supported on the upper end of the leg 64 or 66.On the upper end of the shaft 82 is affixed a supporting head 86 whichhas flanges extending up and around the lower flange of thecorresponding stringer 30-36 to help support and position it. The handle84 is turned downwardly on the'shaft 82 to raise it and the head 86, andis turned upwardly on the shaft to lower it into the leg and lower thehead 86. This adjustable feature of the frame 62 is important to enablethe various stringers to be supported at predetermined levels so that apredetermined number of layers of reinforcing bars supported above thestringers will always be at the same upper level so as to be a givendistance under the upper surface of the concrete 20. Also, theadjustable frames enable the stringers to be supported in a trulyhorizontal position even though the supporting surface 12 may not belevel.

It is necessary that each of the spaced frames 62 be connected to atleast one adjacent frame in order to provide lateral stability for thesupporting network of the frames 62. For this purpose, the legs 64 and66 have appropriately spaced studs or pins 88 (FIG. 5) affixed theretoand extending from the leg in the plane of the frame, either inwardly oroutwardly, extending inwardly as shown, each of the pins 88 having agravityoperated latch 90. Pairs 92 of diagonal braces 94 and 96 extendbetween the corresponding legs 66 of two of the spaced frames 62, withthe ends of the braces being flattened and having holes punched thereinto enable them'to be fitted over and received on the pins 88. Thelatches yield to enable the brace ends to be slid thereover but thendrop down by gravity to prevent unwanted removal of the brace ends.Pairs 98 of braces 100 and 102 also extend between the correspondinglegs 64 in a manner similar to the pairs 92. The number of the pairs 92or 98 of the diagonal braces 94, 96, or 100, 102 will depend, to asubstantial extent, on the height of the legs 64 and 66. However, in anyinstance, at least one of the pairs of braces will be employed and,further, the braces are always employed in pairs affixed to thecorresponding legsat the same corresponding height. Substantially theentire height of each of the legs should be braced, leaving at the mostonly short distances at the ends which are not braced.

Because the stringers 30-34 extend radially outwardly from the centralportion of the slab 22, the adjacent, braced pairs of frames 62 alsomust be positioned in a non-parallel manner relative to one another sothat they can lie in vertical planes through which the stringers 30-34extend. To achieve this, the braces of the pair 92 or 98 are ofdifferent lengths, the pairs 98, in this case being shorter, to achievethe converging position of the frames 62 toward the central portion ofthe slab or the diverging position in a direction toward the periphery.

The braces must be supplied in a manner of lengths, not only to providethe divergent or convergent relationship of the brace frames 62, butalso to accommodate the different spacing of the stringers as theyextend away from the central portion, as shown schematically in FIG. 2.As is also shown there, the outer supporting frames are used to supportthe adjacent stringers whereas toward the center of the structure, theframes support alternate stringers in some instances. Inner ends of someof the stringers 34, as shown in FIG. 3, are supported on singleadjustable supporting posts 104. Also in some instances, asschematically represented in FIG. 2, three adjacent frames may be bracedtogether, rather than being braced in pairs.

With the reinforced construction shown, after the lower mat 16 ofreinforcing bars 2-28 is fabricated on or near the surface 12, theframes 62 are positioned with the pedestals 78 located in spaces betweenthe reinforcing bars 24-28 on the surface 12. The frames 62 for each ofthe stringers are arranged in vertical, radially-extending planes inpositions corresponding to the stringers. With the frames 62 erected andthe appropriate length braces 92 and 98 installed, the stringers canthen be positioned on the supporting heads 86 and the upperreinforcingbars placed thereover. With this arrangement, the overallfabrication or construction time for the reinforced structure is muchshorter than otherwise possible, resulting in a substantial savingsinlabor Various modifications of the above described embodiment of theinvention will be apparent to those skilled in the art and it is to beunderstood that such modifications can be made without departing fromthe scope of the invention, if they are within the spirit and the tenorof the accompanying claims.

We claim:

1. In combination, means forming a firm supporting surface, a lowermultiplicity of reinforcing members located in predetermined positionsabove and near said supporting surface, an upper multiplicity ofreinforcing members, said upper multiplicity of reinforcing membersincluding lower reinforcing members and upper reinforcing memberssupported on said lower ones, at least some of the lower ones of theupper multiplicity of reinforcing-members extending in a divergingmanner from a commmon location, means'supporting the upper multiplicityof reinforcing members in predetermined locations spaced above thesupporting surface, said supporting means comprising a plurality offrames, each having two spaced, parallel uprights and cross bars affixedto and connecting said uprights, adjustable means supported on the upperends of said uprights and having means to engage some of said uppermultiplicity of reinforcing members with the supporting framecorresponding to one of said diverging members bieng located in avertical plane parallel thereto, with the supporting frame for anotherone of said diverging members being located in a vertical plane parallelthereto and spaced from the other frame, diagonal braces extendingbetween corresponding uprights of the spaced frames with the diagonalbraces extending between two of the corresponding uprights of the spacedframes.

being shorter than the diagonal braces extending between the other twocorresponding uprights of the spaced frames, means for removablyattaching said diagonal braces to said uprights, and concrete embeddingall of said members, frames, adjustable means, braces, and attachingmeans and extending from the supporting surface to a level above saidupper multiplicity of reinforcing members.

2. The combination according to claim 1 characterized by said removableattaching means comprises projections extending from said uprights andholes in the ends of said cross braces receiving said projections.

3. The combination according to claim 1 characterized by the lower onesof the upper multiplicity of reinforcing members extend generallyradially from a central area and terminate in a circular periphery.

4. The combination according to claim 3 characterized by said lowermembers which extend radially are positioned and supported by saidframes at a lower level toward the periphery than near the central area.

.plicity of reinforcing members.

5. A reinforced concrete structure which is generally circular inhorizontal cross section comprising means forming a level surface onwhich the structure is located, a multiplicity of elongate reinforcingmembers, said members comprising a plurality of elongate reinforcingmembers extending generally radially from a central portion of saidstructure toward the periphery thereof, means supporting said pluralityof reinforcing members in the predetermined positions spaced above thesurface, said supporting means comprising a plurality of frames, eachincluding two spaced, parallel uprights and connecting cross barsaffixed to said uprights, adjustable jacks supported on the upper endsof said uprights and having means engaging portions of said plurality ofelongate reinforcing members, at least one of said frames beingpositioned so that the adjustable jacks supported on the upper ends ofthe two uprightsengage and support the same radially-extending elongatesupporting member at spaced points, at least another one of said framesincluding two uprights positioned so that the adjustable jacks supportedon the upper ends of these two uprights engage and support anotherradially-extending elongate supporting member at spaced pointscorresponding generally to the spaced points of the firstradially-extending elongate supporting member, two diagonal bracesextending between the two uprights of the two frames which are closer tothe central portion of said structure, said diagonal braces beingconnected by removable attaching means to the correspondinguprights,-and two diagonal braces extending between the two uprights ofthe two frames which are closer to the periphery of said structure, thelatter two diagonal braces being connected by removable attaching meansto the corresponding two uprights, the latter two braces being longerthan the first two braces, and concrete embedding all of said members,uprights, bars, jacks, and braces and extending from the level surfaceto a level above said multi- 6. A reinforced structure according toclaim 5 characterized by said removable attaching means comprisesprojections extending from said uprights and holes in the ends of saidcross braces receiving said projections.

ing lower flanges of said stringers.

1. In combination, means forming a firm supporting surface, a lowermultiplicity of reinforcing members located in predetermined positionsabove and near said supporting surface, an upper multiplicity ofreinforcing members, said upper multiplicity of reinforcing membersincluding lower reinforcing members and upper reinforcing memberssupported on said lower ones, at least some of the lower ones of theupper multiplicity of reinforcing members extending in a divergingmanner from a commmon location, means supporting the upper multiplicityof reinforcing members in predetermined locations spaced above thesupporting surface, said supporting means comprising a plurality offrames, each having two spaced, parallel uprights and cross bars affixedto and connecting said uprights, adjustable means supported on the upperends of said uprights and having means to engage some of said uppermultiplicity of reinforcing members with the supporting framecorresponding to one of said diverging members bieng located in avertical plane parallel thereto, with the supporting frame for anotherone of said diverging members being located in a vertical plane parallelthereto and spaced from the other frame, diagonal braces extendingbetween corresponding uprights of the spaced frames with the diagonalbraces extending between two of the corresponding uprights of the spacedframes being shorter than the diagonal braces extending between theother two corresponding uprights of the spaced frames, means forremovably attaching said diagonal braces to said uprights, and concreteembedding all of said members, frames, adjustable means, braces, andattaching means and extending from the supporting surface to a levelabove said upper multiplicity of reinforcing members.
 2. The combinationaccording to claim 1 characterized by said removable attaching meanscomprises projections extending from said uprights and holes in the endsof said cross braces receiving said projections.
 3. The combinationaccording to claim 1 characterized by the lower ones of the uppermultiplicity of reinforcing members extend generally radially from acentral area and terminate in a circular periphery.
 4. The combinationaccording to claim 3 characterized by said lower members which extendradially are positioned and supported by said frames at a lower leveltoward the periphery than near the central area.
 5. A reinforcedconcrete structure which is generally circular in horizontal crosssection comprising means forming a level surface on which the structureis located, a multiplicity of elongate reinforcing members, said memberscomprising a plurality of elongate reinforcing members extendinggenerally radially from a central portion of said structure toward theperiphery thereof, means supporting said plurality of reinforcingmembers in the predetermined positions spaced above the surface, saidsupporting means comprising a plurality of frames, each including twospaced, parallel uprights and connecting cross bars affixed to saiduprights, adjustable jacks supported on the upper ends of said uprightsand having means engaging portions of said plurality of elongatereinforcing members, at least one of said frames being positioned sothat the adjustable jacks supported on the upper ends of the twouprights engage and support the same radially-extending elongatesupporting member at spaced points, at least another one of said framesincluding two uprights positioned so that the adjustable jacks supportedon the upper ends of these two uprights engage and support anotherradially-extending elongate supporting member at spaced pointscorresponding generally to the spaced points of the firstradially-extending elongate supporting member, two diagonal bracesextending between the two uprights of the two frames which are closer tothe central portion of sAid structure, said diagonal braces beingconnected by removable attaching means to the corresponding uprights,and two diagonal braces extending between the two uprights of the twoframes which are closer to the periphery of said structure, the lattertwo diagonal braces being connected by removable attaching means to thecorresponding two uprights, the latter two braces being longer than thefirst two braces, and concrete embedding all of said members, uprights,bars, jacks, and braces and extending from the level surface to a levelabove said multiplicity of reinforcing members.
 6. A reinforcedstructure according to claim 5 characterized by said removable attachingmeans comprises projections extending from said uprights and holes inthe ends of said cross braces receiving said projections.
 7. Areinforced concrete structure according to claim 5 characterized by saiduprights being tubular and said adjustable jacks including threadedshafts extending inside the upper ends of said uprights, and threadednuts engaged on said shaft and supported on the upper ends of saiduprights, lower ones of said multiplicity of reinforcing members beingI-beam stringers, and said threaded shafts have generally U-shaped headsengaging lower flanges of said stringers.